Driving lug structure for endless track

ABSTRACT

A driving lug for an endless track member for a snowmobile, said lug comprising a seamless metal ring-like member having a core of rubber fabric material bonded thereto with said core having a transverse rod of said track member disposed therethrough and bonded thereto for a unitary construction.

ite ttes Qetrulo, Jr.

[54] DRIVING LUG STRUCTURE FOR ENDLESS TRACK [75] Inventor: Franlr A.Cetrulo, ;lr. ,Eort Thomas,

[73] Assignee: National Factors, Inc., Cincinnati,

Ohio

[22] Filed: Sept. 10, 1971 21 App1.No.: 179,313

[52] U.S. Cl. ..305/38 [51] Int. Cl. ..B62d 55/24 [58] Field of Search..305/35 EB, 38

[5 6] References Cited UNITED STATES PATENTS 3,285,677 11/1966 Marier..305/38 51 all. 27, N73

3,451,729 6/1969 Roy ..305/38 3,508,796 4/1970 Paulson... ..305/383,612,625 10/1971 Huber ..305/38 Primary Examiner-Richard J. JohnsonAttorneyLeo Gregory [57] ABSTRACT A driving lug for an endless trackmember for a snowmobile, said lug comprising a seamless metal ring-likemember having a core of rubber fabric material bonded thereto with saidcore having a transverse rod of said track member disposed therethroughand bonded thereto for a unitary construction.

2 Claims, 3 Drawing Figures Patented March 27, 1973 3,722,963

INVENTOR. FRANK 4- (72040 JR.

DRIVING LUG STRUCTURE FOR ENDLESS TRACK BACKGROUND AND SUMMARY OFINVENTION One of the problems in connection with a driving belt orendless track member for a snowmobile is in connection with the drivinglug members thereof. Said lug members are engaged by the sprocketsdriving the belt. It is a common practice to crimp a metal ring about arubber fabric core to form the driving lug. The lug members aresubjected to a considerably amount of shock and hard wear uponengagement by sprocket teeth and become deformed and separated at theirad joining ends. Replacement of said lug members is a frequentoccurrence.

It is an object of this invention in connection with an endless trackmember for a snowmobile to provide a tubular or ring like seamlessdriving lug member which is bonded to a core of rubber fabric and whichhas a portion of the transverse reinforcing rod of the track memberdisposed therethrough in bonded relationship to said core. Thus, thereis formed here a driving lug member carried by a transverse rod memberhaving a shock absorbing core of rubber fabric which core is bonded bothto said lug member and to said transverse rod whereby in effect aunitary integral driving lug structure is formed. The lug member has noseams to become broken or separated and much of the shock to which it issubjected is absorbed by its rubber core which provides sufficientresilience to the lug member as a whole to prevent the same frombecoming deformed. Thus, the lug members throughout the track member inbeing preserved in their original form provide regular spacingtherebetween for engagement by the driving sprocket.

Generally stated, it is an object of this invention to provide anendless track member for a snowmobile comprising driving lug membersformed of seamless tubular members whereby said lug members arepositioned in the mold in which the end less track member is formed,locating pins position said lug members about portions of the transverserods of said track member, rubber fabric -material in a liquid state isdisposed within said lug members and about the transverse rod portionstherein. Said rubber fabric material is cured within said lug member tobecome bonded to both said lug member and said rod portions therein toform an integral unitary driving lug structure.

It is more specifically an object of the invention herein to provide adriving lug member for the track member of a snowmobile wherein said lugmember has a resilient core bonded thereto and to a transverse rodmember of said track member to absorb the shock to which said lug memberis subjected by driving sprockets and to prevent the deforming of saidlug members.

These and other objects and advantages of the invention will be setforth in the following description made in connection with theaccompanying drawings in which like reference characters refer tosimilar parts throughout the several views and in which:

FIG. 1 is a fragmentary view in plan of an endless track member ofasnowmobile;

FIG. 2 is a view in transverse vertical section on an enlarged scaletaken on line 2--2 of FIG. 1 as indicated; and

FIG. 3 is a view in vertical longitudinal section on an enlarged scaletaken on line 33 of FIG. 1 as indicated.

DESCRIPTION OF A PREFERRED EMBODIMENT Referring to the drawings, afragmentary view is shown of an endless drive belt or track member 10 asfor a snowmobile.

Said track member as here illustrated comprises a central body portion12 and outer side body portions 14 and 16 of narrower width spacedtherefrom at either side thereof respectively forming spaced areas 20and 22 therebetween which are narrow in width and will be furtherdescribed. Said body portions will be formed of a fabric of rubber-likecomposition suitable for forming said endless track.

The inner portion 18 of said track member will be smooth. The outer orground engaging surface of said track member will have transverse raisedrib or cleat portions as indicated by the reference numerals 24, 26 and28 respectively.

Holding said body portions of said track member in transverse spacedrelation and reinforcing the same are transverse rod members 30 eachbeing comprised as here shown of a superposed pair of said rods 30a and30b respectively.

By conventional methods said rods will be positioned in a mold such asan injection mold into which will be introduced the material in liquidform to make up the track structure in connection with said rod members.

Said rod members extend through said spaced areas 20 and 22 at suchintervals longitudinally of said track member as to form sprocket teethapertures 32 therebetween.

Carried by said rod members in said spaced areas 20 and 22 and extendingbetween the central body portion 12 and the respective side bodyportions 14 and 16 are driving lug members 35. Said driving lug membersas hereinafter described comprise the essential subject matter of theinvention herein.

Driving lugs are required in a snowmobile endless track member forengagement by sprocket teeth to move the vehicle. Snowmobile endlesstrack members generally have transverse reinforcing rods of some kindwith portions thereof defining or separating sprocket tooth aperturesand clamped about said portions of said rods are metal ring like membersto provide a wear surface. Said ring like members are generally merelyclamped about said portions of said rods and the rigidity of the metalis relied upon to retain said members in operating position. The ends ofsaid ring like members with said members in position cannot be weldedtogether without injuring or destroying adjacent portions of the trackmember.

The invention herein provides improvement in the structure of saiddriving lug members.

In molding the endless track member of the disclosure herein, as abovedescribed, the transverse rods are positioned in a mold to be embeddedin the rubber composition of the track member to have said rubbercomposition cured thereabout for adhesion or bonding thereto. Theimprovement herein consists of positioning in a mold about each of saidrods within the spaced areas 20 and 22, above indicated, a seamlessmetal band or ring like metal member forming said driving lug member 35.Said lug member is here shown to be oval in longitudinal section havingshallow longitudinal concavities 35a and 35b at the upper and lowersides thereof.

With said lug member 35 positioned in a mold about said rods, asindicated, the rubber composition material of the track member in liquidform will be injected into the mold to fill the area about said rodswithin each of said members 35 to be cured therein for adhesion orbonding to said rods and to the inner surface of said members 35 to makean integral unitary structure whereby said members 35 and said rods 30will be mutually bonded to the rubber composition material therebetween.Thus said lug members 35 have anchored therein a very effective internalinsulating body which absorbs the effect of the stress resulting fromthe engagement of sprocket teeth with said lug members.

Said members 35 may also be initially positioned about said transverserods and placed in a temporary mold to have said rubber compositiondisposed therein and partially cured. Said transverse rods and said lugmembers 31 may thereafter be placed in the regular track mold in whichthe entire track is formed and the rubber material disposed in saidmembers 35 is then fully cured. This may result in better adhesion thanby initially placing said lug members 35 about said rods within thetrack mold.

In operation in a conventional structure as above indicated, with wearclips or driving lugs being clamped in position, the clips are free ofunitary engagement with the transverse rods. Said lugs are generallyformed of a strip of metal material clamped about said rods with anappropriate device. The clips are subjected to considerable pounding bythe engagement of sprocket teeth with the result that the wear clipsbecome deformed and loosened about said rods.

The improvement herein as described consists of providing a seamlessring member positioned about the transverse rods of the track member andhaving bonded thereto the rubber composition material of which the trackmember is formed. Thus the lug members are integral and unitary with thetransverse rods and the rubber composition material therebetween. Thereis no independent or relative movement of the lug member with respect toits internal cushion of rubber composition material. In being unitarywith the rubber material there results very little deformation of thelug member and said lug member provides long lasting service. Inmaintaining its form said lug member preserves regular spacing betweenthe sprocket tooth apertures for precise and regular engagement of saidlug members by the sprocket teeth. The specific area of novelty in thestructure herein is present in being bonded to a cushion body thereinand in turn having this cushion body bonded to the transverse rodportion therein. This structure represents substantial improvement insnowmobile track construction. I

It will of course be understood that various changes may be made inform, details arrangement and proportions of the parts without departingfrom the scope of the invention herein which, generally stated, consistsin an apparatus capable of carrying out the objects above set forth, inthe parts and combinations of parts disclosed and defined in theappended claims.

What is claimed is: 1. An endless track member as for a snowmobilecomprising a belt of rubber composition material arranged to pass oversprocket wheels and be driven thereby having in combination,

a central body portion, a side body portion at either side of saidcentral body portion and spaced therefrom, rods disposed transverselythrough said track member spaced longitudinally thereof connecting saidcentral body portion and said side portions holding the same in spacedrelation and forming spaced areas therebetween, said rods in spacedrelation forming sprocket tooth apertures therebetween within saidspaced areas, a seamless ring like member disposed about each portion ofsaid rods within said spaced areas, rubber composition material disposedwithin each of said ring like members and about each respective rodportion therein, and said rubber composition material being bonded toeach of said ring like members and to said rod portion therein forming aunitary integral driving lug structure. 2. The structure set forth inclaim 1 having in combination,

an endless body portion of rubber composition material,

rods disposed transversely through said track member spacedlongitudinally thereof, longitudinally aligned apertures in said trackmember inwardly of either side thereof forming sprocket tooth aperturesbetween adjacent of said rod members,

a seamless ring like member disposed about each of said rod portionshaving said sprocket tooth apertures spaced therebetween,

rubber composition material disposed within each of said ring likemembers and about the respective rod portions therein, and

said rubber composition material being bonded to said ring like membersand said rod portion therein to form a unitary integral driving lugstructure.

1. An endless track member as for a snowmobile comprising a belt ofrubber composition material arranged to pass over sprocket wheels and bedriven thereby having in combination, a central body portion, a sidebody portion at either side of said central body portion and spacedtherefrom, rods disposed transversely through said track member spacedlongitudinally thereof connecting said central body portion and saidside portions holding the same in spaced relation and forming spacedareas therebetween, said rods in spaced relation forming sprocket toothapertures therebetween within said spaced areas, a seamless ring likemember disposed about each portion of said rods within said spacedareas, rubber composition material disposed within each of said ringlike members and about each respective rod portion therein, and saidrubber composition material being bonded to each of said ring likemembers and to said rod portion therein forming a unitary integraldriving lug structure.
 2. The structure set forth in claim 1 having incombination, an endless body portion of rubber composition material,rods disposed transversely through said track member spacedlongitudinally thereof, longitudinally aligned apertures in said trackmember inwardly of either side thereof forming sprocket tooth aperturesbetween adjacent of said rod members, a seamless ring like memberdisposed about each of said rod portions having said sprocket toothapertures spaced therebetween, rubber composition material disposedwithin each of said ring like members and about the respective rodportions therein, and said rubber comPosition material being bonded tosaid ring like members and said rod portion therein to form a unitaryintegral driving lug structure.